This invention relates generally to a thermostat control, and specifically to a method of conserving energy when the heating or cooling demands on a utility reaches a relatively high peak level.
The increasing demand for electrical energy oftentimes produces an overload condition upon many utilities, particularly during periods of extreme temperatures when the consumers are calling for high levels of energy to satisfy their heating and cooling needs. Currently, some utilities are employing a load shedding system to reduce the power demands during peak power consumption periods. When the customers"" demand for energy reaches a given high level, a utility company that utilizes a load shedding program will send a message to specially equipped thermostats located in specific consumer facilities instructing the thermostat to adjust the preset temperature setting by a fixed number of degrees to reduce the power consumption, and thus the load upon the utility during a given period of time when the demand is expected to be exceptionally high.
The intended reduction in demand, however, may not necessarily be accomplished by many of these prior art systems for a number of reasons. First, a fixed amount of set point adjustment will usually result in a different amount of load shedding in each of the buildings that are being serviced due to differences in building construction and the type and size of the heating and cooling equipment utilized in the structures. Second, the thermostat setting within many of the buildings may be at some extreme set point at the time of a load shedding period. The set back adjustment will thus have little or no effect and the heating or cooling equipment will run continuously during the load shedding period. For example, if a cooling system is set at 70xc2x0 F. on a day when the outside temperature is 100xc2x0 F., setting the thermostat to 72xc2x0 F. will have no effect and the equipment will continue to run throughout the peak demand period without satisfying the demand of the thermostat. Lastly, many buildings are now equipped with programmable thermostats that might be in a setback mode at the time a shedding period is commenced. Typically, the setback mode is utilized when the occupants of a dwelling are at work and the dwelling is unoccupied. When a load shedding instruction is received by the thermostat when it is in an xe2x80x9cunoccupiedxe2x80x9d mode setting, the thermostat will, in many cases, automatically go into a preprogrammed xe2x80x9coccupiedxe2x80x9d mode setting during the load shedding period thereby increasing the load demand rather than reducing it during the shedding period.
It is therefore an object of the present invention to conserve energy.
It is a further object of the present invention to reduce the amount of energy consumed by equipment used to heat and/or cool buildings, particularly during periods when peak power is in demand.
A still further object of the present invention is to provide a system for load shedding that takes into consideration factors involving a structure""s heat loss and other load related characteristics.
Another object of the present invention is to preprogram a thermostat with load shedding data so that the thermostat can respond to a coded input to reduce power consumption as a function of the indoor and outdoor temperatures as well as the building""s heat loss and load characteristics.
Yet a still further object of the present invention is to precondition the heating and cooling system of a building in advance of a load shedding period to allow the building to store energy prior to the period and thus help reduce the load demand during the load shedding period.
Still another object of the present invention is to reset thermostats that have previously setback during a load shedding period so as to minimize the impact of the recovery.
These and other objects of the present invention are attained by a load shedding thermostat having a processor for received coded input signals from an energy provider. When energy demands are predicted to be exceptionally high, one or more input signals are sent to the thermostat to adjust the temperature setting to an energy saving level. The adjusted setting, unlike other setback thermostats, is not a fixed value, but rather is based upon normal heating or cooling operations determined prior to the initiation of a load shedding period. The adjusted load shedding settings take into consideration indoor and outdoor temperatures and factors involving the building""s heat loss and load characteristics.